Perturbations of the local gravity field due to mass distribution on precise measuring instruments: a numerical method applied to a cold atom gravimeter

We present a numerical method, based on a FEM simulation, for the determination of the gravitational field generated by massive objects, whatever geometry and space mass density they have. The method was applied for the determination of the self gravity effect of an absolute cold atom gravimeter which aims at a relative uncertainty of 10-9. The deduced bias, calculated with a perturbative treatment, is finally presented. The perturbation reaches (1.3 \pm 0.1) \times 10-9 of the Earth's gravitational field.Comment: 12 pages, 7 figure

Housing Environmental Risk in Urban Areas: Cross Country Comparison and Policy Implications

The main aim of this paper is to assess whether there is a statistically significant environmental impact of cities within European countries. Second, starting from the estimated environmental impact of cities within European countries, the paper investigates whether cross-country variation can be explained by macro-economic factors and government policies which can play a role in mitigating such an impact. We start from individual evidence (EU-SILC data) to obtain a measure of the environmental impact of cities within countries, and then correlate the latter with macro variables to explain European heterogeneity. These estimates confirm that the environmental risk for households is particularly perceived in more densely populated urban agglomerations, although the marginal effects are quite heterogeneous between countries. Macroeconomic factors such as inequality, wealth, taxation and public spending on the environment, and macroeconomic constraints such as the public finance disequilibrium produce a strong heterogeneity between countries in determining the marginal effects of urban metropolises on household environmental risk

How good are your fits? Unbinned multivariate goodness-of-fit tests in high energy physics

Multivariate analyses play an important role in high energy physics. Such analyses often involve performing an unbinned maximum likelihood fit of a probability density function (p.d.f.) to the data. This paper explores a variety of unbinned methods for determining the goodness of fit of the p.d.f. to the data. The application and performance of each method is discussed in the context of a real-life high energy physics analysis (a Dalitz-plot analysis). Several of the methods presented in this paper can also be used for the non-parametric determination of whether two samples originate from the same parent p.d.f. This can be used, e.g., to determine the quality of a detector Monte Carlo simulation without the need for a parametric expression of the efficiency.Comment: 32 pages, 12 figure

The influence of gas expulsion and initial mass-segregation on the stellar mass-function of globular star clusters

Recently de Marchi, Paresce & Pulone (2007) studied a sample of twenty globular clusters and found that all clusters with high concentrations have steep stellar mass-functions while clusters with low concentration have comparatively shallow mass-functions. No globular clusters were found with a flat mass-function and high concentration. This seems curious since more concentrated star clusters are believed to be dynamically more evolved and should have lost more low-mass stars via evaporation, which would result in a shallower mass-function in the low-mass part. We show that this effect can be explained by residual-gas expulsion from initially mass-segregated star clusters, and is enhanced further through unresolved binaries. If gas expulsion is the correct mechanism to produce the observed trend, then observation of these parameters would allow to constrain cluster starting conditions such as star formation efficiency and the time-scale of gas expulsion.Comment: accepted for publication in MNRAS, 10 pages, 6 figure

Genome-wide SNP discovery and population structure analysis in pepper (Capsicum annuum) using genotyping by sequencing

BACKGROUND: Knowledge on population structure and genetic diversity in vegetable crops is essential for association mapping studies and genomic selection. Genotyping by sequencing (GBS) represents an innovative method for large scale SNP detection and genotyping of genetic resources. Herein we used the GBS approach for the genome-wide identification of SNPs in a collection of Capsicum spp. accessions and for the assessment of the level of genetic diversity in a subset of 222 cultivated pepper (Capsicum annum) genotypes. RESULTS: GBS analysis generated a total of 7,568,894 master tags, of which 43.4% uniquely aligned to the reference genome CM334. A total of 108,591 SNP markers were identified, of which 105,184 were in C. annuum accessions. In order to explore the genetic diversity of C. annuum and to select a minimal core set representing most of the total genetic variation with minimum redundancy, a subset of 222 C. annuum accessions were analysed using 32,950 high quality SNPs. Based on Bayesian and Hierarchical clustering it was possible to divide the collection into three clusters. Cluster I had the majority of varieties and landraces mainly from Southern and Northern Italy, and from Eastern Europe, whereas clusters II and III comprised accessions of different geographical origins. Considering the genome-wide genetic variation among the accessions included in cluster I, a second round of Bayesian (K = 3) and Hierarchical (K = 2) clustering was performed. These analysis showed that genotypes were grouped not only based on geographical origin, but also on fruit-related features. CONCLUSIONS: GBS data has proven useful to assess the genetic diversity in a collection of C. annuum accessions. The high number of SNP markers, uniformly distributed on the 12 chromosomes, allowed the accessions to be distinguished according to geographical origin and fruit-related features. SNP markers and information on population structure developed in this study will undoubtedly support genome-wide association mapping studies and marker-assisted selection programs. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12864-016-3297-7) contains supplementary material, which is available to authorized users

Comparison of in situ devices for the assessment of pavement subgrade stiffness

The subgrade is the top surface of a roadbed upon which the pavement structure is constructed. The purpose is to provide a platform for construction of the pavement and to support the pavement without unwanted deflection that would reduce its performance. For those reasons subgrade bearing capacity have to be investigate during the construction process as a quality control, based on the design results. The dynamic in situ Falling Weight Deflectometer (FWD) tests are nowadays widely used and considered the most reliable and suitable approach to determine bearing capacity of road pavements and elastic moduli. In addition, the use of the Light Weight Deflectometer (LWD) takes the advantage of the dynamic application of load, and the flexibility of the handling of the equipment on construction area and unbound layer. In the present paper, a wide literature review is presented on the topic of correlation between different subgrade bearing capacity in situ tests. In order to assess the transferability of LWD measures, these results were compared with FWD test and Dynamic Cone Penetrometer (DCP) test. Soil samples, taken from the site, have also been investigate in laboratory to relate geotechnical and in situ test results

Histamine plasma levels and elimination diet in chronic idiopathic urticaria

Abstract: Objective: The aim of this study was to evaluate the effects of an oligoantigenic and histamine-free diet on patients affected with chronic idiopathic urticaria (CIU). Design: Ten patients with chronic idiopathic urticaria were prescribed an oligoantigenic and histamine-free diet for 21 days, followed by serial and controlled reintroduction of foods during a further 70 days. Modification in clinical illness as well as histamine plasma levels, post-heparin plasma diamine oxidase (DAO) and intestinal permeability were evaluated. Results: The oligoantigenic and histamine-free diet induced a significant improvement of symptoms (P < 0.05). Moreover, CIU patients on free diet showed higher histamine plasma levels (P < 0.05 vs post-diet and vs controls) that fell to control levels during the oligoantigenic and histamine-free diet. Post-heparin plasma diamine oxidase values were slightly reduced and were unchanged during the diet as well as intestinal permeability, which was always normal in all patients. Conclusions: These data suggest that histamine plays a major role in chronic idiopathic urticaria. The finding of normal intestinal permeability suggests that a morphological damage of intestinal mucosa should be excluded in these patients. However, the presence of low levels of post-heparin plasma diamine oxidase may indicate a subclinical impairment of small bowel enterocyte function that could induce a higher sensitivity to histamine-rich or histamine-producing food

Evaluating the environmental impact of crude glycerol purification derived from biodiesel production: A comparative life cycle assessment study

In recent decades, surplus crude glycerol has been generated in large amounts as a waste product of biodiesel production, leading to bottlenecks in the supply chain of the biodiesel industry. This waste glycerol represents an important potential renewable feedstock and platform chemical; however, its purification is often needed for further processing. Advancements towards glycerol purification are being made using sustainable purification techniques aimed at improving the biodiesel industry's environmental footprint. Many studies focussing on various techniques to purify glycerol can be found in the literature; however, very few studies to evaluate the environmental impacts of the purification processes have been reported. This paper provides a critical investigation on the cradle-to-gate life cycle assessment (LCA) of three different processes for purifying crude glycerol, namely, physicochemical treatment and membrane purification (PMP) processes, vacuum distillation purification (VDP) processes and ion exchange purification (IEP) processes having a functional unit (FU) of 1000 kg of purified glycerol. These purification processes were modelled using Aspen plus software v12.1 in combination with Super Pro Designer v13. CCaLC2 (Carbon Calculations over the Life Cycle of Industrial Activities) was used to measure the environmental impacts associated with each process. By following the ISO 14044:2006 methodology and utilising the CCaLC2 tool, seven different types of potential environmental impacts have been investigated, which include carbon footprint, water footprint, acidification, eutrophication, ozone layer depletion, photochemical smog and human toxicity. Sensitivity analysis of the LCA was carried out using the response surface method (RSM) to determine the most effective parameter within the LCA. The total carbon footprint of the PMP, VDP and IEP processes are 3466.82, 1745.72 and 2239.71 kg CO2 eq. FU−1 respectively. The LCA study determined that waste generated as a result of crude glycerol impurities from the three processes had one of the highest environmental impacts on the overall process. For the PMP and IEP processes, the raw materials used in the physicochemical treatment also contribute significantly to the carbon footprint and other environmental impacts. Lastly, aspects concerning the environmental impacts from the PMP glycerol purification process have been addressed by analysing the raw materials from different sources accompanied by altered waste disposal methods (i.e. the incineration of generated wastes as opposed to landfilling) in an attempt to reduce the overall environmental impacts. For the PMP process, which has the highest carbon footprint, usage of differently sourced raw materials and altered waste disposal treatments resulted in 39% reduction in total carbon footprint and 54% reduction in the total ozone layer depletion. Sensitivity analysis of the LCA shows that the glycerol content within the crude glycerol was the most significant parameter

Yield scaling, size hierarchy and fluctuations of observables in fragmentation of excited heavy nuclei

Multifragmentation properties measured with INDRA are studied for single sources produced in Xe+Sn reactions in the incident energy range 32-50 A MeV and quasiprojectiles from Au+Au collisions at 80 A MeV. A comparison for both types of sources is presented concerning Fisher scaling, Zipf law, fragment size and fluctuation observables. A Fisher scaling is observed for all the data. The pseudo-critical energies extracted from the Fisher scaling are consistent between Xe+Sn central collisions and Au quasi-projectiles. In the latter case it also corresponds to the energy region at which fluctuations are maximal. The critical energies deduced from the Zipf analysis are higher than those from the Fisher analysis.Comment: 30 pages, accepted for publication in Nuclear Physics A, references correcte

Estimate of average freeze-out volume in multifragmentation events

An estimate of the average freeze-out volume for multifragmentation events is presented. Values of volumes are obtained by means of a simulation using the experimental charged product partitions measured by the 4pi multidetector INDRA for 129Xe central collisions on Sn at 32 AMeV incident energy. The input parameters of the simulation are tuned by means of the comparison between the experimental and simulated velocity (or energy) spectra of particles and fragments.Comment: To be published in Phys. Lett. B 12 pages, 5 figure